This invention relates generally to lock devices for semitrailers and the like, and more particularly to devices for preventing the unauthorized operation of a dolly wheel or a landing gear system of a semitrailer.
Thefts or unauthorized movements of semitrailers are a serious and expensive problem. Virtually all modern semitrailers used to handle freight and merchandise of any sort are equipped with large, over-the-road rear truck wheels, and a dolly wheel or landing gear system is located near the front of each trailer. When the semi truck driver wants to disconnect or xe2x80x9cdropxe2x80x9d the trailer he is pulling, he stops his truck at the desired location and then engages and turns a dolly wheel or landing gear crank handle, usually located on the left side of the trailer near the trailer front. This crank handle operates a dolly wheel or landing gear system to lower small, relatively rigid wheels or skids into engagement with the pavement or ground directly under the front of the semitrailer. Further operating the crank handle slightly raises the trailer front so as to disengage the trailer kingpin from the truck tractor or cab. When the trailer is disengaged, the truck driver can drive the tractor or cab away.
Some thieves believe it is easy to reposition or steal these dropped, standing trailers. These thieves simply bring another tractor to the trailer, engage the kingpin, raised the dolly wheels or landing gear, and drive the cab and now-connected trailer to a secluded location where the trailer can be opened and robbed. Lock devices to prevent unauthorized access to the trailer kingpin are awkward to install and remove, messy, and sometimes ineffective.
It is therefore important to be able to secure the dolly wheel or landing system in its lowered, ground-engaging position. If the dolly wheels or landing gear cannot be raised to a traveling position, the trailer cannot be moved. If the trailer cannot be moved, thieves are discouraged from attempting to rob the trailer. Alternatively, it may be desirable to secure the dolly wheels or landing gear in the raised position, so as to prevent thieves from disengaging the trailer from a parked trailer tractor or cab.
Several devices have been offered to prevent unauthorized access to the semitrailer dolly wheel or landing gear systems. One such device is described and illustrated in U.S. Pat. No. 5,782,115. Another device, denominated as The Enforcer Landing Gear Lock, is offered by Transport Security, Inc. of Waconia, Minn. A relatively inexpensive method of securing the landing gear crank handle against unauthorized movement is to wrap a length of chain around the handle and an adjacent landing gear stanchion or other fixture, and then secure the chain by a padlock. Some of these devices or arrangements are expensive, or complicated, or ineffective.
It is therefore the general object of this invention to provide a strong, secure lock for a truck semitrailer to prohibit unauthorized movement of the trailer.
It is a more specific object of the invention to provide a strong and secure lock device for a truck semitrailer to prohibit unauthorized operation of the trailer dolly wheel or landing gear system.
It is another object of the invention to provide a unitary, one-piece, rigid lock box adapted to fit over portions of the semitrailer dolly wheel or landing gear system so as to prevent unauthorized operation of that system.
It is an ancillary object to provide a lock device for a truck semitrailer which is low in manufacturing cost but high in strength and effectiveness.